1. Field of the Invention
The present invention relates to a rotary self-propelled endoscope system which inserts into the body of a subject an elongated flexible tube provided with a helical portion around the outer circumference thereof.
2. Description of the Related Art
A medical endoscope enables observation of the interior of a body cavity with an elongated insertion section thereof inserted into the body cavity. Further, if necessary, the medical endoscope enables therapeutic treatment with a treatment instrument inserted into a forceps channel included in the endoscope.
The endoscope includes a bendable bending portion on the distal end side of the insertion section. The bending portion is moved and bent in the vertical or horizontal directions through the operation of a bending operation knob. The endoscope is inserted into an intricate lumen in the body cavity, such as a lumen forming a 360° loop including the large intestine, for example. In the insertion operation, a surgeon inserts the insertion section toward a site to be observed, while operating the bending operation knob to bend the bending portion and performing a twisting operation of the insertion section.
However, a high level of skill is required for the surgeon to be able to rapidly and smoothly insert the insertion section into a deep part of the intricately shaped large intestine while performing the bending operation and the twisting operation. In inserting the insertion section into the deep part of the large intestine, an inexperienced surgeon may lose the insertion direction or substantially change the lying shape of the intestine.
In light of the above, a variety of proposals have been made to improve the insertability of the insertion section. For example, Japanese Unexamined Patent Application Publication No. 10-113396 discloses a propelling device for a medical instrument capable of guiding the medical instrument into a deep part of a lumen in a body cavity with ease and with low invasion.
In the propelling device, an oblique rib with respect to the axial direction serving as a propulsive force generator is provided to a rotary member. When the rotary member is rotated in the propelling device, the rotational force of the rotary member is converted into the propulsive force by the rib. Thereby, the medical instrument connected to the propelling device is moved by the propulsive force toward the deep part.
Endoscopes using the above-described technique are divided into a variety of types. For example, endoscopes transanally inserted into the large intestine include a rotary self-propelled endoscope apparatus including an insertion section provided with a flexible and axially rotatable rotary tubular member around the outer circumference of the insertion section. According to the rotary self-propelled endoscope apparatus, the endoscope can be automatically inserted into a body cavity through the rotation of the rotary tubular member.